Programs commonly use the REP STOS instruction of the x86 instruction set architecture to scrub memory, e.g., to fill it with zeroes, or to write a large amount of the same data to a video buffer. The amount of data to write specified in ECX may be relatively large such that many cache lines and even many pages of memory are written. The goal is for the processor to do this as fast as possible. Typically, the memory being written has a write-back memory trait, meaning it is writeable and cacheable. If the store area (i.e., the area of memory being written) is already in cache, the REP STOS will go much faster than if the store area is missing in the cache. This is because the processor must allocate missing cache lines, i.e., gain ownership of the cache lines and read them in from memory into the cache, which is very relatively time consuming.